Corteks proposes to develop a micro-processor controlled self-optimizing amplifier specifically designed to record evoked potentials under adverse conditions. The device will have very high common-mode-noise rejection, superior anti-aliasing and reduced susceptibility to stimulus artifact compared to currently commercial devices. it is anticipated that these features will make this amplifier significantly better suited for recording evoked potentials in electrically noisy environments, and for performing evoked potential studies which are currently difficult or impossible because of stimulus artifact. These performance characteristics will be achieved by incorporating several digitally controlled analog components in critical places in the amplifier circuit, and using an on-board dedicated micro-processor to optimize amplifier function. In Phase I, an initial prototype will be designed and built, and the effectiveness of the proposed techniques will be critically evaluated. In the Phase II prototype, we will replace the simple digital pass-band filter used in Phase I with a substantially more powerful digital signal processor, enhance the amplifier input switch to support automatic rapid montage switching, and expand the role of the micro-processor to provide stimulator control.